Asiolasma billsheari, Martens, 2019

Martens, Jochen, 2019, An ancient radiation: Ortholasmatine harvestmen in Asia - a new genus, three new species and a revision of the known species (Arachnida, Opiliones, Nemastomatidae), Revue suisse de Zoologie 126 (1), pp. 79-110 : 104-107

Asiolasma billsheari sp. nov.

Figs 1 , 104-117

Holotype: SMF; male; CHINA, Gansu Province, western part of Qinling Mountains, 125 km northwest of Longnan, southern side of Lazikou pass, Zhuli valley , 2260 m, 34°07’57’’N, 103°56’15’’E, north slope, mixed oak/pine forest near creek, moss and litter sifted; D.W. Wrase leg.; 3.8.2012.

Paratype: CJM 8146; 1 male; collected together with holotype .

Diagnosis: A relatively small species with rather flat body and short hood; only prolonged anterior part of prosoma with eye mound and hood slightly elevated, similar to geographically close species A. juergengruberi sp. nov. from northern Yunnan; body less massive than in A. schwendingeri sp. nov. from northern Vietnam, caused by smaller hood processes. Pt of pedipalp with a bent and pointed medio-distal apophysis; areae I-IV of opisthosoma with one paramedian pair of low tubercles.

Name: The species is dedicated to William A. Shear, an esteemed arachnologist and myriapodologist who, together with Jürgen Gruber, meticulously studied New World ortholasmatine harvestmen. Name in genitive case.

Description

MALE

Body, dorsal side ( Fig. 104-105 ): Body rather flat but less so than in A. schwendingeri sp. nov. (la view); Tu oc on anterior margin of prosoma only slightly elevated, with a rather low ascent and only slightly elevating eyes; these close to anterior margin of prosoma and hardly integrated into proximal portion of hood, central hood tubercle slightly bent upwards (la view); hood bearing one central unpaired and four or five (unequal on left and right side) lateral paired tubercles, basic one shortest (less than half size of next one or nearly equal size of following one; number of tubercles different on left and right side of hood; Fig. 104 ), the following ones consecutively longer, last one shorter than central unpaired one; all tubercles interconnected by small anvil-shaped bridges close to their bases; on both sides of hood one short and one long apophysis projecting from anterior margin of prosoma and closely flanking hood, these apophyses thick and massive, covered by small warts. Posterior margin of opisthosoma with a row of 14 tubercles of different lengths, slightly tapering towards markedly rounded tips, longest tubercles in centre and in right part of row. Areae I-IV of opisthosoma with one para-median pair of low indistinct pegs, distal pair shortest, all others of about equal size (do/la view).

Network of keel cells indistinct, only few closed ones on prosoma laterally; on prosoma scattered anvil-shaped tubercles also in curved transverse rows; on metapeltidium one transverse row of tubercles; on opisthosoma keel cells nearly lacking, no closed cells except for few small ones near lateral margins and additional smaller ones on area V of scute near posterior margin, these cells not always closed; 1-2 transverse rows of anvil-shaped tubercles on areae I-IV of scute partly interrupted.

Body, ventral side: Cx with longitudinal rows of low light tubercles, similar tubercles on Op gen, free sternites and corona analis; free tergites bent to ve side, with transverse rows of tubercles as well.

Legs: Short, brownish, without darker marks; Fe I and F II slightly swollen, Fe II with slight shallow constrictions; fine microtexture on all articles except Mt and Ta, the latter with fine setae. Tarsal articles of legs I-IV of holotype, of male paratype in parenthesis; in Ta I different numbers on right and left side: I 6 (5/6), II 9 (9), III 6 (6), IV 6 (6).

Chelicera ( Figs 112-114 ): Posterior part of basal article markedly invaginated dorsally (la view), set with one long elevated seta dorsally and few small setae dorso-distally; 2nd article with a strong massive apophysis on upper side, ending in a pointed hook, bent in anterior direction; rounded rather flat apophysis-like edge below hook (la view). Setae of various sizes situated on hook, otherwise mainly on frontal and prolateral sides of article. Only broad apophysis, not pointed hook visible in la view: no brush of setae present and no obvious glandular tissue.

Pedipalp ( Figs 115-117 ): Tr slender, slightly swollen on do side; two small tubercles distally on ve side, each pointed and carrying a strong seta; Fe long and slender, slightly bent downwards, slightly enlarged distally, set with few scattered normal hairs, no clavate hairs; Pt markedly enlarged and bulge-like ventrally except for basal part, ventrally and partly prolaterally with a dense field of short setae, no apparent glandular tissue below this brush-like field, a small pointed ventro-prolateral hook close to distal margin of article; Ti cylindrical and slender, with indistinct basal stalk, not curved, with loose cover of clavate hairs on all sides; Ta slenderer than Ti, distinctly stalked, slightly inflated on do side, densely covered with clavate setae all round, distally few long and thin setae interspersed.

Genital morphology ( Figs 106-111 ): Penis very long and slender, more than two-thirds of body length, slightly curved, short basis deeply split into two parts, two muscles concentrated there, penis shaft partly parallelsided, partly continuously tapering to level of proximal pair of spicules and slightly depressed (ve/la view); penis (la view) markedly broadened at base and extremely slender above, only slightly enlarged towards glans; glans spindle-shaped and broadened (la view); stylus short and in straight continuation of glans, with slight helical torsion, opening of sperm duct subdistal, sperm in distal end of sperm duct.

Spicules of glans nearly uniform in size and spindleshaped, arranged in four groups between distal portion of glans and distal part of truncus: i) two spicules on do side, ii) six spicules forming ring on ve, la and do sides, iii) two spicules on each lateral side, iv) one spicule on each lateral side on truncus well below glans armature.

FEMALE: Unknown.

Variation: The armature of the glans is the same in both specimens available. Otherwise no data can be given due to the lack of sufficient material.

Relationships: This species occupies a rather isolated position, but it appears to be closely related to the other species with a massively elevated apophysis of the 2nd cheliceral article, A. ailaoshan and A. juergengruberi sp. nov. Asiolasma ailaoshan is strikingly different in its sexual dimorphism, i.e. the sole known female is much larger than the corresponding male. This dimorphism may also be revealed when the unknown female of A. billsheari is discovered. The apophysis of the hood is (absolutely and relatively) shorter in A. billsheari sp. nov., thus forming a less broader and less palmate fan cover for pedipalps and chelicerae than in A. schwendingeri sp. nov. The minute pegs on the do side of the opisthosoma are absent in A. ailaoshan and A. schwendingeri sp. nov.

Measurements: Body length (including hood and opisthosomal tubercles) of males: 3.0-3.05 (n=2). Leg II: Tr 0.3, Fe 2.6, Pt 0.8, Ti 2.0, Mt 2.0, Ta 1.6. Pedipalp: Tr 0.3, Fe 0.7, Pt 0.4, Ti 0.45, Ta 0.8. Penis length: 1.7.

Distribution ( Fig. 1 ): The species is only known from the type locality in the Chinese Gansu Province at about 34°N and represents the northernmost known locality of ortholasmatines on mainland Asia (and in Asia in general including the Japanese records of Cladolasma parvulum ). The two specimens were collected from soil litter in a pine and oak forest at 2260 m altitude.

Figures

Fig. 1. Distributional records of ortholasmatine species in East and Southeast Asia. (1) Asiolasma billsheari sp. nov., China, Gansu, Qinling range. (2) A. juergengruberi sp. nov., China, Yunnan, above Lugu Hu. (3) Same species as before, China, north of Lijiang. (4) A. ailaoshan, China, Yunnan, Ailao Shan. (5) A. damingshan, China, Guangxi, Daming Shan. (6) A. schwendingeri sp. nov., Vietnam, Mt Ba Vi. (7) A. angka, Thailand, Doi Inthanon. (8) Dendrolasma parvulum, Japan, Shikoku Island.

Figs 104-111. Asiolasma billsheari sp. nov., male holotype (104, 106-111), male paratype (105). (104) Entire body dorsal view. (105) Same lateral view. (106) Glans penis in lateral view. (107) Same in ventral view. (108) Same in dorsal view. (109) Truncus penis in lateral view. (110) Same in dorsal view. (111) Same in ventral view. In Figs 106-108 subdistal opening of sperm duct is indicated, end of sperm duct is filled with sperm. In Fig. 105 armament with low tubercles on do and ve side of body not shown. Scales: 0.1 mm (106-108); 0.3 mm (104-105, 109-111).

Figs 112-117. Asiolasma billsheari sp. nov., male holotype. (112) Right chelicera in prolateral view. (113) Same in retrolateral view. (114) Apophysis of 2nd cheliceral article in prolateral view. (115) Pedipalp in prolateral view. (116) Distal part of pedipalpal femur, whole patella and proximal part of tibia in retrolateral view. (117) Apophysis on ventro-distal part of pedipalpal patella in prolateral view. Scales: 0.1 mm (114); 0.2 mm (112-113); 0.3 mm (115-116); no scale (117).